Hello all! Having worked for a while with various computer systems, primarily Active Directory and Exchange, I wanted to share some of my experiences with two objectives in mind: 1) obtain feedback to improve my mastery of those systems and 2) help others working on the same subject. Other posts are about CentOS, Citrix NetScaler, and VMware.
NOTE: most of my posts are in English but some others in French, with a summary in English. However, some of the CentOS blog posts lack this summary.

Monday, August 29, 2016

Exchange 2010 (SP3) - Message Tracking - 04

In reverse order of complexity, I finished by sending a message from one internal user (Alan Reid) to another internal user (Alannah Shaw) who both have their mailbox in the same mailbox database. I then replied to the message.

As a reminder, we have two Exchange servers (EX13-1 and EX13-2) configured in a Database Availability Group (DAG) with the active copy of the (sole) mailbox database currently on EX13-2.

First message - Alan Reid to Alannah Shaw

The Message Tracking logs on EX13-2 show two events (EventID): a NOTIFYMAPI event which provides some information about the message and then a SUBMIT event.

Note: I had not included the NOTIFYMAPI events in my previous blog posts but will show one example below simply so we can see what it looks like. And once again, I have edited out some parameters (essentially those without values) for simplicity and concision.

According to one discussion I followed, it appears that the first entry is associated with the Mailbox role that notifies the Hub Transport role of the presence of a message (in the Outbox of the user?).

We should keep in mind that the Hub Transport role is responsible for ALL message delivery, even when a message goes from one mailbox to another in the same mailbox database.

In that context, it is interesting to observe (in the screenshot above) that the Hub Transport role on EX13-2 (where the active copy of the mailbox database is located) submits the message to EX13-1 (here again, the Hub Transport role manages the mail flow).

But what happens next? To see, we have to change our perspective to EX13-1 where the message is briefly in transit (presumably in the Transport database - yes there is a transport database also, where messages reside for a more or less short period while in transit).

EX13-1

In the two screenshots below, we see that EX13-1 receives the message from EX13-2 (EventID = RECEIVE) and then delivers the message to the recipient Alannah Shaw (EventID = DELIVER).

Since there is no DELIVER event in the EX13-2 message tracking logs, it seems clear that EX13-1 places the message in the recipient mailbox.

There is an abundance of additional information related to the Hub Transport role and mail flow online. In particular, there is a chart that helps visualize the processing of messages, the "Overview of the transport pipeline in Exchange 2010" chart available here: